Loud speaker for wireless telephony and other purposes



June 14,1927. 1,632,287 P. GRASSMANN LOUD SPEAKER FOR WIRELESS TELEPHONYAND OTHER PURPOSES Filed March 20, 1925 1 8 1 /'V I? E ///1 g 5 v 116 Av "51:; 17

q mi 'i i A 6 15s 1% .ll l 46 2F ii I 41 Patented June 14, 1927.

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Application filed latch 20, 1925, Serial Io.'17,128, and in Germany lebruary 9, 1985.

This invention relates to improvements in .loud speakers comprisin asound box mounted ona telephone casing. and of the kind in whichan'electro-magnetically op- 6 erated pivoted armature mounted in thetelephone casing is connected to a vibrat-.

ing diaphragm mounted in the sound box through the intermediary of aControlling ivoted member and in which the latter is 1'0 inked to thepivoted armature at a point which is eccentric with respect'to thecentre of the armature and the centre-ofthe diaphragm.

Two forms of construction according to the present invention areillustrated by way of example in the accompanying drawings, in which IFigures 1 and 2 illustrate in sectional elevation and plan viewrespectively one form,

tion can be ensured between them by-me'a'ns of fixing screws 'in a wellknown manner, The magnetic system of the telephone may consist of theusual permanent magnets 3 of horse-shoe shape, having pole shoesprovided with coils 4. The pole surfaces 5 and the end surface of thecasing 1 are ound simultaneously thereby ensurin' t at all thesesurfaces shall lie in one an the same plane. The armature 6' is arran edat a short distance from the ole sur aces, and it consists of a lever w'ch is arranged to oscillate for instance about an axle 7 surrounded bya helicalspring and is provided with a flat flexible extension 8 which;rests upon an adjusting 9;.

The lower surface of the armature 6 is also ground so as to form a flatsurface 'which.

will be arallel to the le surfaces,- its distance rom thelatter ingadjusted by means of insertions 10. The displacement ofthe pin 9required for the fine regulation is effected b means of an eccentricshaft 11 provided wlth a controlling knob 12 and passing transverselythrough the hole 13 iii-which the adiusting pin 9 is giided, the

Referring to the form of construction il- 'il'rfrla ifi nets 4"wh1chareene'r' zed in such a manwithdrawn axially. The. turning of the knob -12causes the pin 9 to be shifted in its axial direction, therebyregulating the sensitiveness of the armature. The armature 6 carries asupport or bearing 16 arranged eccentrically with respect to the centreof the armature, the controlling member 18 mounted in the-sound box bemgrotatably secured to the said bearing, and the latter lying between therocking .point 17v and the arm of the controlling member which isconnected to the diahragm. .The pivot in the support 16 may beconstituted by a screw or screws screwed in laterally, so that the soundbox and the telephone casin may be manufactured entlrely. separate y andbe secured to ether subsequently, the connection between-t 0' armature 6and the controlling member 18- being effectedsimply by screwin in theplvot screw or screws throu 'h suita le holes formed in the sidewall ofthe sound box;

' A particular advantage ofthe arrange- Referring to the arran eme'nt'illu'strated in Figure 3 the same di ers from that described withreference to Figures 1 and 2 by the telephone casing being constructed(parts 1, lathe armature '6 being so as to oscillate between two mag-- Ihit they shall o opposite polarities, and the flatflexible arm 8 at theend of the armatiire'bein secured to the ia'gg'iusting' pin 9- The box2' is moun cpaxially with the. two parts 1 if of the telephone casingwhilst the support 16 of the controlling member 18 projects through thecasin' 1.

It is to be understood that in both forms of construction the aperture20 prov ded in the sound box is intended to efiect commum istancebetween the mid e ofan armature pivota ly mounted therein, a

wall separating the sound box from the telephone casing, a controllingpivoted member in the sound box connected to the centre of the diaphragmand a connecting member between the said controllin member and thearmature, the points 0 connection of the connecting member with the saidcontrolling member and with the armature respectively being eccentricwith respect to the centre thereof and thecontrolling member'pa'ssingthrough the wall separat ng the sound box from the telephone casing" asset forth.

2. A loud speaker comprising in combination a sound box having avibrating diaphragm mounted therein, a telephone casing having anelectrically controlled magnet and an armature constructed in the formof a lever capable of oscillating about a point lying on the edge of thetelephone casing, a controlling member pivoted in the sound box andconnected to the centre of the diaphragm and a support on the armaturewhich lies eccentrically with respect to the centre of the telephonecasing. and supports the controlling member between the rockin point ofthe latter' and the centre of t e diaphragm, as set forth.

3. ,A loud speaker comprising in combi nation a soun fihragm' mountedtherein, a telephone casing aving an electrically controlled magnet andan armature pivotally mounted therein, a controlling pivoted member inthe sound bo'x connected to the centre of the'diaphragm, a

connecting member'between the said controlling member and the armature,the points of connection of the connecting member with the saidcontrolling member and with the armature respectively being eccentricwith respect to the centres thereof, an adjustable pin in thetelephone'casing and anextension on the armature which extension is supported by the said adjustable pin, as set forth. I i

4. A loud speaker as claimed in claim 3 and in which the extension ofthe armature is secured to the adjustable pin as set forth.

52A loud speaker comprlsmg in combination a two part telephone casing,an electrically controlled ,magnet in each part thereof, an armaturebetween the said two parts, a sound box with 1 vibrating diaphragmmounted on the two-part telephone casing 'coaxially therewith, acontrolling member within the sound box connected to the centre of thediaphragm, and a connecting member between. the said controlling memberand ,the armature, the pointsof connection of the connecting memberwith.

the armature and the controlling member respectively being eccentricwith respect to the centres thereof, as set forth,

In testimony whereof. I have signed my name to this specification.

PETER GRASSMANN.

box having a vibrating dia-

